diff --git a/Makefile.am b/Makefile.am
index 995ce8c..d4d6680 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -32,6 +32,15 @@ moddir = $(sharedir)/modules
 localedir = @datadir@/locale
 testsdir = $(pkgdatadir)/tests
 
+#define empty global variables
+bin_PROGRAMS =
+mod_PYTHON =
+noinst_HEADERS =
+pkglib_LTLIBRARIES =
+EXTRA_DIST =
+MAINTAINERCLEANFILES =
+MOSTLYCLEANFILES =
+
 # ############################################################
 #
 # additional rules
@@ -57,14 +66,14 @@ macros = m4/compilerflags.m4 \
 	m4/ac_pkg_swig.m4 \
 	m4/ac_python_module.m4
 
-
-EXTRA_DIST = \
+EXTRA_DIST += \
 	config/config.rpath \
 	config/mkinstalldirs \
 	configure.ac \
 	gettext.h \
 	$(macros)
-MAINTAINERCLEANFILES = doc/API
+
+MAINTAINERCLEANFILES += doc/API
 
 # ############################################################
 #
@@ -106,47 +115,6 @@ dist-hook : apidox
 distclean-local :
 	if test -d 'doc/API'; then rm -rf 'doc/API'; fi
 
-# ############################################################
-#
-# source : libpyloader.la
-#
-# ############################################################
-
-pkglib_LTLIBRARIES = src/backend/pyloader/libpyloader.la
-
-src_backend_pyloader_libpyloader_la_CPPFLAGS = \
-		-I@top_srcdir@ \
-		-DPYCDIR="\"$(pycdir)\"" \
-		-DMODDIR="\"$(moddir)\"" \
-		-DLOCALEDIR="\"$(localedir)\"" \
-		$(PYTHON_CPPFLAGS) \
-		$(GLIBMM_CFLAGS)
-src_backend_pyloader_libpyloader_la_CXXFLAGS = \
-		$(VISIB_HIDDEN)
-src_backend_pyloader_libpyloader_la_LIBADD = \
-		$(PYTHON_LDFLAGS) \
-		$(PYTHON_EXTRA_LIBS) \
-		$(GLIBMM_LIBS) \
-		src/backend/libbackend.la
-src_backend_pyloader_libpyloader_la_LDFLAGS = \
-		$(PYTHON_EXTRA_LDFLAGS) \
-		$(LT_LDFLAGS) \
-		-version-info 0:0:0
-
-# Please keep this in sorted order:
-src_backend_pyloader_libpyloader_la_SOURCES = \
-		src/backend/pyloader/python_policy.cc \
-		src/backend/pyloader/python_policy_manager.cc
-
-noinst_HEADERS = \
-		src/backend/pyloader/python_policy.hh \
-		src/backend/pyloader/python_policy_manager.hh
-
-mod_PYTHON = \
-		src/backend/pyloader/Abstract.py \
-		src/backend/pyloader/Policy.py \
-		src/backend/pyloader/ScriptAdapter.py
-
 # ############################################################
 #
 # source : libbackend.la
@@ -210,7 +178,7 @@ noinst_HEADERS += \
 # ############################################################
 
 # Program & library names
-bin_PROGRAMS = sgpemv2
+bin_PROGRAMS += sgpemv2
 
 sgpemv2_CPPFLAGS = \
 		-I@top_srcdir@ \
@@ -254,6 +222,47 @@ noinst_HEADERS += \
 	src/start_gui.hh \
 	src/text_simulation.hh
 
+# ############################################################
+#
+# source : libpyloader.la
+#
+# ############################################################
+
+pkglib_LTLIBRARIES += src/backend/pyloader/libpyloader.la
+
+src_backend_pyloader_libpyloader_la_CPPFLAGS = \
+		-I@top_srcdir@ \
+		-DPYCDIR="\"$(pycdir)\"" \
+		-DMODDIR="\"$(moddir)\"" \
+		-DLOCALEDIR="\"$(localedir)\"" \
+		$(PYTHON_CPPFLAGS) \
+		$(GLIBMM_CFLAGS)
+src_backend_pyloader_libpyloader_la_CXXFLAGS = \
+		$(VISIB_HIDDEN)
+src_backend_pyloader_libpyloader_la_LIBADD = \
+		$(PYTHON_LDFLAGS) \
+		$(PYTHON_EXTRA_LIBS) \
+		$(GLIBMM_LIBS) \
+		src/backend/libbackend.la
+src_backend_pyloader_libpyloader_la_LDFLAGS = \
+		$(PYTHON_EXTRA_LDFLAGS) \
+		$(LT_LDFLAGS) \
+		-version-info 0:0:0
+
+# Please keep this in sorted order:
+src_backend_pyloader_libpyloader_la_SOURCES = \
+		src/backend/pyloader/python_policy.cc \
+		src/backend/pyloader/python_policy_manager.cc
+
+noinst_HEADERS += \
+		src/backend/pyloader/python_policy.hh \
+		src/backend/pyloader/python_policy_manager.hh
+
+mod_PYTHON += \
+		src/backend/pyloader/Abstract.py \
+		src/backend/pyloader/Policy.py \
+		src/backend/pyloader/ScriptAdapter.py
+
 # ############################################################
 #
 # C++ modules -> Python loadable modules
@@ -283,7 +292,7 @@ _sgpem_la_LIBADD = src/backend/libbackend.la \
 _sgpem_la_SOURCES = $(wrappers)
 
 EXTRA_DIST += $(_sgpem_la_INTERFACES)
-MOSTLYCLEANFILES = $(proxies) $(wrappers)
+MOSTLYCLEANFILES += $(proxies) $(wrappers)
 
 # ############################################################
 #